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Characterization of poly-4-hydroxybutyrate mesh for hernia repair applications

David P. Martin, PhD; Amit Badhwar, PhD; Devang V. Shah, PhD; Said Rizik, MS; Stephen N. Eldridge, MS; Darcy H. Gagne, BS; Amit Ganatra, MS; Roger E. Darois, BEng; Simon F. Williams, PhD; Hsin-Chien Tai, PhD; and Jeffrey R. Scott, PhD

Journal of Surgical Research 184(2):766-773.2013

Link to Publication:


Background: Phasix mesh is a fully resorbable implant for soft tissue reconstruction made from knitted poly-4-hydroxybutyrate monofilament fibers. The objectives of this study were to characterize the in vitro and in vivo mechanical and resorption properties of Phasix mesh over time, and to assess the functional performance in a porcine model of abdominal hernia repair.

Materials and Methods: We evaluated accelerated in vitro degradation of Phasix mesh in 3 mol/L HCl through 120 h incubation. We also evaluated functional performance after repair of a surgically created abdominal hernia defect in a porcine model through 72 wk. Mechanical and molecular weight (MW) properties were fully characterized in both studies over time.

Results: Phasix mesh demonstrated a significant reduction in mechanical strength and MW over 120 h in the accelerated degradation in vitro test. In vivo, the Phasix mesh repair demonstrated 80%, 65%, 58%, 37%, and 18% greater strength, compared with native abdominal wall at 8, 16, 32, and 48 wk post-implantation, respectively, and comparable repair strength at 72 wk post-implantation despite a significant reduction in mesh MW over time.

Conclusions: Both in vitro and in vivo data suggest that Phasix mesh provides a durable scaffold for mechanical reinforcement of soft tissue. Furthermore, a Phasix mesh surgical defect repair in a large animal model demonstrated successful transfer of load bearing from the mesh to the repaired abdominal wall, thereby successfully returning the mechanical properties of repaired host tissue to its native state over an extended time period.


Dr. Simon Williams is a Consultant to Tepha, Inc. and a member of the Tepha Board of Directors. Dr. David Martin is the Chief Scientific Officer of Tepha, Inc. Said Rizik, MS, Amit Ganatra, MS, Jeffrey R. Scott, PhD are employees of Tepha, Inc.